textproduct: Quad Cities

KEY MESSAGES

- Hot and humid conditions persist into the weekend with highs around 90 to near 95 and heat indices in the 90s to around 100F. A Heat Advisory remains in effect for portions of NE Iowa and NW Illinois this afternoon.

- Wildfire smoke will be around in our skies into the weekend, making for hazy sunshine and vibrant sunrises and sunsets. The smoke is likely to remain mostly aloft, and could be dense enough at times to limit high temperatures by a few degrees. - Shower and storm chances gradually increase for the end of the week and beginning of the weekend.

- Pattern change next week will bring periodic storm chances and cooler temperatures.

SHORT TERM /THROUGH THURSDAY/

Issued at 233 PM CDT Wed Jul 15 2026

The short term forecast remains hot and humid as surface high pressure sits just to our west in eastern Nebraska. Aloft, a 596 dam ridge continues to steer disturbances and wildfire smoke around us. Today, surface heating beneath this ridge has supported the development of diurnal cumulus across much of Iowa, Missouri, and western Illinois. Despite the scattered clouds and light winds, temperatures have reached the upper 80s to low 90s across the area, with heat indices in the upper 90s to low 100s. As a result, no changes have been made to the Heat Advisory for parts of northwestern Illinois and northeastern Iowa for this afternoon and evening. There is low confidence in advisory criteria being met over the next several days despite the extended period of heat, primarily due to the arrival of wildfire smoke and increasing chances for precipitation as we approach the weekend.

Tonight, temperatures to drop into the low 70s. There is potential once again for patchy fog, especially in river valleys, due to light winds and mostly clear skies allowing for radiational cooling. Additionally, a weak boundary will move away from Lake Michigan and sit across Wisconsin and northern Illinois. If this boundary were to progress further into northwestern Illinois, a shower or two could be possible. However, much of the guidance keeps this to our northeast. As a result, any precipitation chances will be limited until Thursday afternoon, when forcing associated with a weakening upper low will arrive. Due to the broad weak forcing, isolated chances (10-30%) for showers are most likely through the evening, with the highest chances along the boundary to the northeast.

LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/

Issued at 233 PM CDT Wed Jul 15 2026

Hot and humid conditions look to persist into the weekend with highs around 90 to near 95F and heat index readings from the mid 90s to around 100F. There remains uncertainty with highs continuing into the weekend due to the potential for Canadian wildfire smoke, as an upper jet extends across the Upper Midwest and Great Lakes. It is possible that higher concentrations of smoke, both aloft and near the surface, reach parts of northwestern Illinois by Friday as seen in the HRRR and RRFS, though there is still quite a bit of spatial spread in the near-surface smoke.

Increasing moisture with some Gulf input along with a weakening upper low and vort max lifting northward toward the region will lead to shower and storm chances mainly Friday PM. The greater coverage (possibly 50-70%) will be favored Friday afternoon into evening south/east of the QC metro being in closer proximity to the better forcing from the weakening upper low. While we'll have ample CAPE both days, very weak shear should keep any storms that develop disorganized and short-lived. Primary risk with these storms will be gusty winds (low risk for isolated severe) with precip loading and as cell collapse. Slow motions will lead to the potential for localized heavy downpours potentially 1"+.

The pattern is set to undergo a change toward broad eastern troughing and western ridging over the weekend into next week. A series of shortwaves or ridge riders on the edge of the "ring of fire" out west should result in periodic storm chances. Can't rule out some severe threat at times in the northwest flow aloft, but plenty of uncertainties in timing/strength/ location of these waves at this range. What is of higher confidence is a return to cooler/seasonable temperatures next week with the Climate Prediction Center (CPC) latest 6-10 day outlook showing some signal (30-40%) for leaning below normal July 20-28. We may see some signs of this transition toward more seasonable conditions as early as Sunday, particularly across our north/east counties as surface ridging temporarily builds down through the Great Lakes.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 613 PM CDT Wed Jul 15 2026

Light and variable winds will be seen through tonight and into Thursday, becoming more southerly after 15z. Between 06-12z tonight, we will once again see the chance for patchy dense fog. These conditions look to be favored in our north, largely at DBQ and CID, but guidance is hinting at the potential throughout the area. Opted to include mention in the TAFs with 4SM and mist at this time. Will update accordingly when confidence in coverage increases. Around 12z, the fog should clear, leaving us with another mostly clear day. There will be a chance for isolated-scattered showers/storms after 18z, but confidence in timing and coverage is low at this time.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory until 8 PM CDT this evening for IAZ042-054. IL...Heat Advisory until 8 PM CDT this evening for ILZ001-002-007. Air Quality Alert until midnight CDT Thursday night for ILZ001- 002. MO...None.